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United States Patent | 5,663,971 |
Carlsten | September 2, 1997 |
Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies.
Inventors: | Carlsten; Bruce E. (Los Alamos, NM) |
Assignee: | The Regents of the University of California, Office of Technology (Alameda, CA) |
Appl. No.: | 626661 |
Filed: | April 2, 1996 |
Current U.S. Class: | 372/2; 315/5; 372/33; 372/37; 372/64; 372/82 |
Intern'l Class: | H01S 003/00 |
Field of Search: | 372/2,64,33,82,37 315/5,4 |
4298824 | Nov., 1981 | Walsh | 315/5. |
4809281 | Feb., 1989 | Neil et al. | 372/2. |
4825441 | Apr., 1989 | Marshall et al. | 372/2. |
4835446 | May., 1989 | Nation et al. | 315/5. |
5015914 | May., 1991 | Ives et al. | 315/5. |
5280490 | Jan., 1994 | Conde et al. | 372/37. |
Bruce E. Carlsten, "Stable Off-Axis Electron Orbits In A Longitudinal-Wiggler Free-Electron Laser," 78, American Institute of Physics, No. 4, pp. 2811-2816 (Aug. 1995). Rita G. Lerner, Series Editor, "Advanced Accelerator Concepts," in AIP Conference Proceedings 156 1986 (American Institute of Physics, pp. 394-410). no month available. H. Takeda et al., "Stable Off-Axis Electron Orbits and Their Radiation Spectrum In A Helical Wiggler," A237 Nuclear Instru. & Methods in Phy. Research, pp. 145-153 (1985) no month avail. P. Volfbeyn et al., "Measurement of the Temporal and Spatial Phase Variations of a Pulsed Free Electron Laser Amplifier," 22 IEEE Trans. Plasma Sci., p. 659 (1994). no month avail. |